Known can combustors for gas turbines can include an inner liner and an outer liner. At least a portion of air compressed by a compressor part of a gas turbine passes between the inner and outer liners and serves to moderate a temperature of the inner liner. The compressed air can then be intermixed with fuel, and the fuel-air mixture is ignited. This combustion takes place within a space defined by the inner liner.
In some configurations, the inner liner is made of two pieces: an upstream combustion piece and a downstream transition piece. The combustion and transition pieces are connected by an axial seal, such as a hula seal, at the overlap between the pieces. Combustion takes place primarily within the upstream combustion piece, and hot combustion gas is directed by the transition piece to a turbine part of the gas turbine. The combustion and transition piece are thus both directly exposed to the hot combustion gas, except for a section of one of the pieces where they overlap at the hula seal. The temperature difference between the inner and outer liners is less at this location than at other locations because the outer portion of the inner liner at this location is heated less than at other locations. For this reason, it is conventional to fix the inner liner to the outer liner at the location of the hula seal so that a relatively simple connecting structure can be used that is not required to accommodate expansion and contraction of the inner liner relative to the outer liner.
To reduce NOx emissions during operation, lean premix combustion methods can be used. However, this can increase pressure wave oscillations in the combustor as a result of instabilities in burn rate. Unless properly mitigated, noise and vibration, and possibly damage to the combustors, can result. To address this issue in cannular and annular combustors, an attachment of damper boxes with multiple necks to the transition piece has been proposed, for example, in U.S. Pat. No. 6,530,221 B1, the disclosure of which is incorporated by reference herein in its entirety. A multiple damper version arranged around a can combustor has also been proposed in U.S. Application Publication No. 2011/0220433, the disclosure of which is also incorporated by reference herein in its entirety.